Charles Penninger (Penninger Radio) has that "in stock" in western Chicago suburbs (15 miles west of my QTH) You likely also have a local aluminum tubing supplier / distributor in your area -- without having to pay for the shipping charges. 1/8" wall is very nice -- and surprising lightweight for its strength. At the 2 inch diameter size you can use either 1/8" or 1/4" wall http://www.penninger.com/prod05.htm
Greg w9gb
Date: Thu, 22 Nov 2007 14:13:57 -0500 From: "Stargate" [email protected] Subject: [amsat-bb] Mast strength?? To: "Amsat-Bb" [email protected] Message-ID: [email protected] Content-Type: text/plain; charset=iso-8859-1
Hi all,
I am installing 20' of Rohn 45 with a flat top from Normsfab and a Yaesu GS-065 thrust bearing.
The lower end of the tower is already figured out but I'm not sure of what strength 2" mast I need.
All this short tower will be supporting is a 3-4 element 6M homebrew beam just above the bearing on the tower, as well as, the elevation portion of the Yaesu G-5500 rotor with 8' fiberglass cross mast, and M2 2MCP22, and 436CP42UG beams on each end of the cross boom. The 2MCP22 is 2.5 sq ft wind load. The 436CP42UG is 2.0 sq ft wind load. I'm not sure of the WL for the rotor and 6M beam.
The mast will have to be at least 18'-20' long to give 2-3 foot inside the tower to the AZ rotor and enough sticking out the top to give 1/4 wavelength (at 2M) spacing between the satellite antenna's and the 6M beam. The satellite antenna's are close to 20' long and mount from close to the center so I need at least 10' (+1/4 wavelength) above the top of the 6M beam.
I'm not an engineering type so I thought I would ask on here. What thickness and material would the mast need to be to support this.
I am thinking T6061 aluminum, .25" thick wall, 2" outside diameter mast.
I live in a 75mph wind zone.
Any help would be much appreciated.
Thanks, 73's RoD KD0XX